You learn something new every day, or so they say. And it's true - you can find one-day courses on anything from how to conquer your fear of flying to how to drive a steam engine to the basics of website design - all in eight hours. There are even one-day courses on how to run a one-day course.
This intensive format is becoming increasingly common in the world of education. And with the demise of the 20-day national curriculum subject courses, and increasing pressure of work, more and more teachers are taking their annual five days of professional development one day at a time.
But what can you really learn in a day? Well, whatever it is, you'll do it a lot better on a hearty breakfast. Proper nutrition is vital for effective learning.
Bill Lucas, chief executive of the Campaign for Learning, whose forthcoming book, Your Mind: a user's guide, is a kind of operator's manual for the brain, says physical factors can play a big part in mental performance. "The brain is a greedy organ and needs lots of oxygenated blood," he says. "Regular food and water will improve its efficiency."
Dehydration limits the brain's operating capacity, so if you want to get the most out of your day course, drinks lots of water and avoid coffee. Although it is usually offered as a pick-me-up between sessions, its diuretic properties give it the opposite effect.
Indeed, the learning process is sometimes compared to eating, with the fashion for "bite-sized" chunks of information - the politician's soundbite, the newspaper digest, the 30-second television ad - spreading into education. Further education colleges offer short "taster" courses to entice adult returners. And the entire strategy of learndirect - the government scheme to encourage people back into education - is based on "bite-sized" chunks.
But this does not make the one-day course the educational equivalent of fast food. And the notion that a few tempting morsels will stimulate the appetite for learning is more than a marketing gimmick.
Research has shown that the brain learns best in short bursts. Twenty-minute sessions, with breaks so participants can stretch their legs (helping to boost the brain's bloodflow), are ideal. It also aids the brain's habit of remembering the beginning and end of things (think of films and books) by creating lots of them.
"The way information is presented is important," says Bill Lucas. "If a typical secondary school staff of 60 teachers were assessed about the way they prefer to take in information, a third would say they like to read or see things. Another third would like to hear it - they are the kind that don't read pre-conference stuff. And another third prefer to do it kinaesthetically - getting up and doing it."
Most groups of learners conform to these proportions. So if any one style of teaching predominates, two-thirds of the audience will feel left out. The best one-day trainers cater for everybody by varying their approach.
Planning is especially important for a successful one-day course - participants should know what to expect and could be given, for example, a simple research task. Completing it eases any introduction and gives them something to contribute. Their minds are tuned in to the task before they arrive.
Ted Wragg, professor of education at Exeter University, says: "You can learn quite a bit in a day. It all depends how you learn; you don't learn an awful lot sitting and listening to people talking for eight hours. You learn better from doing things.
"You need a good mixture of activity, an authoritative presentation of information, a discussion of the issues, then get them doing something. And you need time to reflect on events and analyse them."
The best in-service course he's been oncentred on a role-play exercise featuring an allegedly incompetent teacher, his union officer, headteacher, and a parent. But the quality of one-day courses is "hugely varied", he says. "Boring presentations that people don't relate to are easily the worst."
Guy Claxton, visiting professor of psychology and education at Bristol University, doubts the usefulness of the one-day format. "One-day courses are driven by considerations of neatness and economic efficiency," he says. "If not followed up they tend to make little difference to anything."
Going on a "team-building" day tackling Krypton Factor-style challenges can be good for morale, he says, but you might not learn much. "Get a bunch of teachers down on the floor to build a bridge out of spaghetti and they have a fun time. But that doesn't build teams. Any insight takes time, and reminding and coaching and modelling."
Ted Wragg says a single day might be better spent meeting staff with similar jobs in other schools. By swapping experiences and strategies in a structured way and with the help of an outside facilitator, they can learn more from each other in a day than they might glean in a week of lectures.
He remembers one such gathering for deputy heads that "absolutely buzzed" with ideas. Delegates were asked in advance to try out several ways of teaching a particular topic or tactics for dealing with unruly pupils, and came to the course brimming with anecdotal evidence.
Such concentrated bouts of career enhancement will remain the norm, so long as the Government sticks to its five days of CPD and insists that additional training should take place in the teacher's own time. Ted Wragg says local management of schools has made the cost of supply cover prohibitive, effectively ruling out longer periods of off-the-job learning.
But, he argues, it's a false economy. "In the 1980s about 2,000 teachers a year were seconded to spend a year doing a master's at university. Some went on to become the best heads and deputy heads you could find. Many people said it changed their lives. There was a real payback.
"The most people can expect now is to get out occasionally for a couple of days - that's just not enough. It's often the most conscientious teachers who are the most committed and they can end up working themselves into the ground."
He would like to see the Government look back nearly 30 years to the 1972 James report's recommendation that teachers should be rewarded with a full term's sabbatical for every seven years' service. "For a profession as demanding as teaching that is a minimum. Instead we get five days a year - which is no substitute."
But when the day is over, remembering and being able to use what was taught is just as important as taking it in in the first place. So using tricks such as humour and variations in style can help. Bill Lucas says: "You can learn a hell of a lot in a day, but if you have forgotten it tomorrow it's no use." He is amazed that so many one-day courses and conferences feature coffee-fuelled, two-hour sit-down sessions. "It's outrageous. Most of this stuff is just common sense."
The Campaign for Learning practises what it preaches by giving its employees five "personal learning days" a year on top of their normal staff development programmes. Driving, drama, music and rock-climbing are a few of the subjects staff have chosen. "Successful learning is about making learning normal, making it part of your everyday life - not about learning with a capital L," says Bill Lucas.
He believes the scheme has helped to build trust and motivation among staff and is part of creating a learning culture. Learning for its own sake in work time is a luxury most teachers, not to mention education authorities, can't afford. With days off for training at a premium, now more than ever, teachers have to ensure it is time well spent.